1. Field of the Invention
The present invention relates to a play-back device such as an audio device, which includes a first operation unit (or a front operation unit) and a second operation unit (or a rear operation unit) for operations to control and output play-back signals from play-back sources having a playback function of recording media such as a CD, an MD, a DVD and so on and a receiving function of an AM/FM radio broadcasts.
2. Description of the Related Art
In recent years, a vehicular audio system provided with a dual medial function is known as such audio device.
An audio device providing with such dual media function includes a plurality of speakers so that it can play back the play-back signals from the play-back sources simultaneously, and makes the directivities of the individual speakers variable, as disclosed in JP-A-11-75284.
With reference to the accompanying drawing, here will be described one example of the vehicular audio system, which is provided with such general dual media function. FIG. 6 is a system construction diagram showing the entire construction of the vehicular audio system having a general dual media function.
The vehicular audio system 100, as shown in FIG. 6, is constructed to include: a body device 101 arranged on the front side in a vehicular compartment and provided with a plurality of play-back sources including a CD playback function and a receiving function of an AM/FM radio; a front operation unit 102 for operating the body device 101 on the front side; a rear operation unit 103 for operating the body device 101 remotely on the rear side in the compartment; and a speaker 104 and a headphone 105 for aurally outputting sound signals coming from the play-back sources of the body device 101.
The speaker 104 is composed of two front speakers 104A arranged on the front side, and two rear speakers 104B arranged on the rear side. On the other hand, the headphone 105 is arranged on the rear side.
Moreover, the play-back sources include the CD playback unit and the AM/FM radio tuner unit, the latter of which acts as an AM tuner and an FM tuner so that it can receive the AM broadcast and the FM broadcast by itself.
Here, the front operation unit 102 corresponds to the front panel, as arranged on the front side, of the body device 101, and the rear operation unit 103 corresponds to the remote operation unit arranged on the rear side.
Moreover, the front operation unit 102 and the rear operation unit 103 are provided a playback mode key (as will be abbreviated into the “MODE” key) for selecting at least one of play-back sources, and a preset key capable of receiving the receiving frequency of the radio broadcasting station registered in advance, by a single-touch operation. Here, the playback modes are exemplified in the CD mode for selecting and operating the CD playback unit as the play-back source, the AM mode for selecting and operating the AM/FM radio tuner unit to receive the AM broadcast, and the FM mode for selecting and operating the AM/FM radio tuner unit to receive the FM broadcast.
Moreover, the front operation unit 102 and the rear operation unit 103 are provided with various action keys including: a track UP/DOWN key for selecting and playing back the track of a CD in the CD mode, a seek UP/DOWN key for seeking and receiving a receiving frequency of the radio, and a mute/pause key for pausing the CD being played back, temporarily and for muting the sound output of the radio broadcast.
Moreover, the body device 101 has a dual media function and can be switched and set to a single mode or a dual mode as the system setting mode in response to a predetermined operation from the front operation unit 102.
In the single mode, the sound signals from one of the play-back sources are aurally outputted exclusively from the speaker 104.
In the dual mode, the sound signals from one of the play-back sources are aurally outputted from the speaker 104, whereas the sound signals from another play-back source are aurally outputted from the headphone 105.
In case the body device 101 is demanded for provisions of sound signals from different play-back sources such that a passenger on the front side requests the FM mode whereas a passenger on the rear side requests the CD mode, the dual mode can be set by operating the front operation unit 102 in a predetermined manner. Then, the sound signals of the FM broadcast can be aurally outputted on the front side from the speaker 104, and the sound signals from the CD playback unit can be aurally outputted on the rear side from the headphone 105.
In short, the front passenger and the rear passenger can accept the sound signals from the different play-back sources through the speaker 104 and the headphone 105.
According to the vehicular audio system 100 having such dual media function, the dual mode can be set in response to the predetermined operation of the front operation unit 102. In this duel mode, the sound signals from the different play-back sources can be provided through the speaker 104 and the headphone 105. Therefore, the front and rear passengers can listen to the sound signals from the different play-back sources. Here in this vehicular audio system 100, it goes without saying that the common play-back source (or the common playback mode) can be selected in the dual mode on the front side and on the rear side so that the sound signals from the common sound source can be provided on the front side and on the rear side.
In the vehicular audio system 100 provided with such dual media function, moreover, all the key operations from the front operation unit 102 and the rear operation unit 103 are effectively accepted even in the single mode and in the dual mode. Therefore, the front and rear passengers can acquire desired actions through those front operation unit 102 and rear operation unit 103.
According to the vehicular audio system 100 having the dual media function, moreover, when the use of a telephone is detected by a telephone interrupting function, the mute/pause function is automatically started to bring the sound signals being aurally outputted into an output-stopped state so that the telephone using environment can be made satisfactory.
According to the vehicular audio system 100 having the aforementioned general dual media function, however, all the key operations of the rear operation unit 103 are effectively accepted even in the dual mode. Although the front passenger brings the CD playback into a temporary stopped state (or an output stopped state) in the dual mode and in the common playback mode such as in the CD mode on the front side and on the rear side by operating the mute/pause key of the front operation unit 102 so as to make conversations, for example, the temporary stopped state is randomly released against the will of the front passenger in response to a predetermined operation of the rear operation unit 103 by the rear passenger.
According to this vehicular audio system 100, moreover, although the CD playback is brought into the temporary stopped state (or the output stopped state) in the dual mode and in the common playback mode such as in the CD mode on the front side and on the rear side by detecting the use of the telephone with the telephone interrupting function, not only the temporary stopped state is randomly released but also even the playback track position is randomly changed against the will of the front passenger by the key operation of the action key of the rear operation unit 103 such as the track UP/DOWN key in the CD mode by the rear passenger.
According to this vehicular audio system 100, moreover, all the key operations of the rear operation unit 103 are effectively accepted even in the single mode. Although the front passenger brings the CD playback into the temporary stopped state in the single mode by operating the mute/pause key of the front operation unit 102 so as to make conversations, for example, the temporary stopped state is randomly released against the will of the front passenger in response to a predetermined operation of the rear operation unit 103 by the rear passenger.
According to this vehicular audio system 100, moreover, the CD playback is brought into the temporary stopped state (or the output stopped state) in the dual mode and in the individual playback modes on the front side and on the rear side such as in the CD mode on the front side by detecting the use of the telephone with the telephone interrupting function. However, the rear operation unit 103 can accept the key operation to control the CD mode on the front side, such as the key operation of the volume control or the track UP/DOWN key operation. Against the will of the front passenger, therefore, the conversations of the front passenger are obstructed by the key operation of the rear operation unit 103 such as the volume control by the rear passenger.